Statistical Quality Control Basic Concepts Product Control Process Control Variations in Quality

Basic Concepts When small samples are taken continuously on a regular basis, and the data analysed statistically, valuable information can be derived. Control charts forms an integral part of production process. Provides timely warning signal & for corrective action.

Basic Concepts The effectiveness of control charts depends on how promptly, the warning is understood and heeded and necessary action taken to correct the process. Helps manufacturer in identifying and eliminating causes for defectives or failures in repetitive production processes.

Statistical Process Control SPC is the primary analysis tool of quality improvement. It is the applied science that helps you collect, organize and interpret the wide variety of information available to your business.

Statistical Process Control - Aim  To Achieve Defect Prevention.  To Pursue Never-ending Improvement.  To Reduce Variability, Delivery Times, Completion Times, Methods, Attitudes, Equipment and Material.  To Produce Components Consistently within Specifications.  to give us Statistical Signal when Special causes of Variation are Present.

Process Control – Tools  Flow chart to understand what is being done.  Check sheets & tally charts to observe the frequency of occurrence of the process.  Graphs to see the pictorial representation of the numbers.  Cause and effect analysis to study the causes of the problems.

Process Control – Tools  Pareto analysis to segregate serious problems from the minor once.  Scatter diagrams to study the relationship between various interacting factors.  Control charts to interpret and decide which variations to control and go about.  Histograms to appreciate as to how the variations in frequency of occurrence appear.

Process Control - Advantages Greater consistency in fulfilling customer's requirements leads to greater customer satisfaction. Reduced variation in internal processes leads to less time and money spent on rework and waste.

Product Control  Product Control helps to ensure that the firm follows the proper regulatory and financial procedures with regard to the firm's business transactions, especially as they relate to issues of customer protection and the liquidity ratio of the firm. It must also reconcile the securities, commodities, futures and fixed income settlements, and monitor the financial and regulatory exposures associated with them, to further ensure the legitimacy of the transactions.

Product Control Reconciliation of P&L to traders estimates and attribution. Control analysis - posting to the ledger, accuracy of P&L. Balance sheet analysis. Internal management reporting. Price verification of all products.

Variations in Quality  Common cause of variation account for 80 – 90 percent of the observed variation in a production unit.  The remaining 10 – 20 percent results from special case of variation, often called assignable causes.  Special causes include bad batch of material purchased, poorly trained operator, excessive tool wear, miscalibration of measuring instrument etc.

Variations in Quality  Common cause of variation account for 80 – 90 percent of the observed variation in a production unit.  The remaining 10 – 20 percent results from special case of variation, often called assignable causes.  Special causes include bad batch of material purchased, poorly trained operator, excessive tool wear, miscalibration of measuring instrument etc.

Variations in Quality  Way to reduce the variation due to common causes is to change the technology of the process – the machines, materials, methods, or measuring systems.  Variation due to special cause can be identified through the use of charts.  Special cause of variations are identified by the production operators and their immediate super visors through charts and make the necessary correction.